For example, in vehicles, a brushless motor is used as a drive source for assisting the rotation of a steering and the like. Moreover, the brushless motor is used also as a drive source which rotates a steering when detecting the lane of a road and a vehicle running immediately ahead, and then automatically operating a vehicle based on a signal of the detection.
As described above, the brushless motor used as the drive source which rotates a steering has been required to have high reliability. Furthermore, the brushless motor has been required to be designed in such a manner as to perform a minimum function even when a failure, such as disconnection, occurs in coils constituting the brushless motor. For example, Patent Literature 1 discloses a configuration such that a switching unit, which is movable between a closed position at which current flows in each phase winding and an open position at which current does not flow, operates when a failure occurs.
Patent Literature 2 discloses a configuration such that two or more power electronics each are provided in a stator having a winding portion separated into two or more portions as a starter generator system of vehicles.